<?php
/**
 * Copyright 2011 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License. You may obtain
 * a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

require_once "php-sdk-3.1.1/base_facebook.php";

/**
 * Extends the BaseFacebook class with the intent of using
 * PHP sessions to store user ids and access tokens.
 */
class SBaseFacebook extends BaseFacebook
{
  /**
   * Identical to the parent constructor, except that
   * we start a PHP session to store the user ID and
   * access token if during the course of execution
   * we discover them.
   *
   * @param Array $config the application configuration.
   * @see BaseFacebook::__construct in facebook.php
   */
  /*public function __construct($config) {
	if (!session_id()) { // Yii should already have started the session
	  session_start();
	}
	parent::__construct($config);
  }*/

  protected static $kSupportedKeys =
	array('state', 'code', 'access_token', 'user_id');

  /**
   * Provides the implementations of the inherited abstract
   * methods.  The implementation uses PHP sessions to maintain
   * a store for authorization codes, user ids, CSRF states, and
   * access tokens.
   */
  protected function setPersistentData($key, $value) {
	if (!in_array($key, self::$kSupportedKeys)) {
	  self::errorLog('Unsupported key passed to setPersistentData.');
	  return;
	}

	$session_var_name = $this->constructSessionVariableName($key);
	Yii::app()->session[$session_var_name] = $value;
  }

  protected function getPersistentData($key, $default = false) {
	if (!in_array($key, self::$kSupportedKeys)) {
	  self::errorLog('Unsupported key passed to getPersistentData.');
	  return $default;
	}

	$session_var_name = $this->constructSessionVariableName($key);
	return isset(Yii::app()->session[$session_var_name]) ?
	  Yii::app()->session[$session_var_name] : $default;
  }

  protected function clearPersistentData($key) {
	if (!in_array($key, self::$kSupportedKeys)) {
	  self::errorLog('Unsupported key passed to clearPersistentData.');
	  return;
	}

	$session_var_name = $this->constructSessionVariableName($key);
	unset(Yii::app()->session[$session_var_name]);
  }

  protected function clearAllPersistentData() {
	foreach (self::$kSupportedKeys as $key) {
	  $this->clearPersistentData($key);
	}
  }

  protected function constructSessionVariableName($key) {
	return implode('_', array('fb',
							  $this->getAppId(),
							  $key));
  }

  /**
   * Prints to the error log if you aren't in command line mode.
   * Overidden to use the Yii log instead of the default server log.
   *
   * @param string $msg Log message
   */
  protected static function errorLog($msg) {
	// disable error log if we are running in a CLI environment
	// @codeCoverageIgnoreStart
	if (php_sapi_name() != 'cli') {
	  //error_log($msg);
	  Yii::log($msg,CLogger::LEVEL_ERROR,'ext.SBaseFacebook');
	}
	// uncomment this if you want to see the errors on the page
	// print 'error_log: '.$msg."\n";
	// @codeCoverageIgnoreEnd
  }
}
